• 국제초고층학회논문집
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• 제2권2호
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• pp.105-113
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• 2013

Recent studies proved turbulent flow properties in high-rise building models differ from those in low-rise building models by comparing turbulent statistics. Although it is important to understand the flow characteristics within and above high-rise building models in the study of urban environment, it is still unknown and under investigation. For this reason, we performed wind tunnel experiment using Particle Image Velocimetry (PIV) to investigate and identify the turbulent flow properties and characteristic flow patterns in high-rise building models. In particular, we focus on instantaneous flow field near the canopy and extracted flow field when homogeneous flow field were observed. As a result, six characteristic flow patterns were identified and the relationship between these flow patterns and turbulent organized structure were shown.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.101-103
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• 2003

This paper deals with field distributions in high speed motor with two different types of diametrically magnetized PM rotor, one is that rotor is consisted of PM and shaft, the other is that rotor has only PM. In case of high speed motor with rotor consisted of PM and shaft, this paper predicts field distributions in high speed motor according to the quality of shaft. The magnetic field solutions are derived analytically in terms of vector potential and 2-D polar coordinate system. The results are shown in good conformity with those obtained from the commonly used finite element method.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
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• pp.403-406
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• 2009

Recently, electricity is essential for human lives. Modem people take cultural benefits due to the development of the electric power system and the spread of the high tech-electric appliances, the cell phones, and etc. However, the electromagnetic field problems become prominent figures owing to the fault of the communication devices around the power line and the biological effect, and etc. In this paper, we introduce the simple electromagnetic field calculation based on the transmission line matrix method, prior to the analysis about the influence of electromagnetic field. Simulation object is the inner part of the trailer car in the high speed train. Unlike the existing paper we submitted, we analyze not only the magnetic field but the electric field in the inner part of the trailer car which makes up the high speed train.

• 한국초전도ㆍ저온공학회논문지
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• 제19권1호
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• pp.51-55
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• 2017

To obtain Nuclear Magnetic Resonance (NMR) measurement of membrane protein, an NMR magnet is required to generate high intensity, homogeneity, and stability of field. A High-Temperature Superconducting (HTS) magnet is a promising alternative to a conventional Low-Temperature Superconducting (LTS) NMR magnet for high field, current density, and stability margin. Conventionally, an HTS coil has been wound by several winding techniques such as Single-Pancake (SP), Double-Pancake (DP), and layer-wound. The DP winding technique has been frequently used for a large magnet because long HTS wire is generally difficult to manufacture, and maintenance of magnet is convenient. However, magnetic field generated by the slanted turns and the splice leads to field inhomogeneity in Diameter of Spherical Volume (DSV). The field inhomogeneity degrades performance of NMR spectrometer and thus effect of the slanted turns and the splice should be analyzed. In this paper, field gradient of HTS double-pancake coils considering the slanted turns and the splice was calculated using Biot-Savart law and numerical integration. The calculation results showed that magnetic field produced by the slanted turns and the splice caused significant inhomogeneity of field.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.171-176
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• 1995

In recent years, Hith Performance Concrete has attracted world wide attention for its workability, strength and long-term durability. A field test was conducted to confirm the properties of high performance Concrete in situconditions. This paper describes the concrete materials, mix proportions, fresh state properties, some aspects of placability and qualty control results for field test. From the result, it was found that it is possible to produce High Performance Concrete with self-compactable and high strength.

• 대한의용생체공학회:의공학회지
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• 제17권1호
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• pp.19-24
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• 1996

이 논문의 목적은 Target field approach방법을 사용하여 2차원적인 공간선택을 할 수 있는 고차 평면 경사 자계코일(High-Order SGC: High-Order Surface Gradient Coil)을 설계하는 것이다. 지금까지 쓰이던 원통형의 고차경사자제코일을 이용한 2차원적 원형 선택방법은 한 개의 RF Pulse로 2차원적인 공간 선택을 할 수 있는 장점이 있었으나 선택되어지는 체적의 지름이 6 ~ 8cm로 너무 크다는 단점이 있었다. 이 논문에서는 이와 같은 단점을 극복하기 위해 영상을 얻고자하는 부분에 코일을 좀 더 가까이 붙일 수 있어서 적은 전력으로 선택되어지는 체적의 지름을 1 ~ 4cm까지 줄일 수 있는 표면 고차자계코일을 Target field approach방법을 이용하여 설계하였으며 Phantom과 인체영상을 통해 제작된 코일의 성능을 확인해 보았다. 이전의 Field component 방법을 이용하여 설계한 코일에 의해서 선택되어지는 체적은 타원에 가까운 모양이 되었으나, Target field approach 방법을 이용하여 설계한 코일에 의해서 선택되어지는 체적은 이상적인 원에 가까운 모양이 되었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권3호
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• pp.93-108
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• 2013

This study is aimed to prepare the effective detail survey methods(Phase II) of abandoned metal mines through the contamination assessment for mine types and facilities in the abandoned metal mine areas. The study sites of 12 abandoned mines are located in Gyeonggi-do and Gangwon-do and those were chosen among 310 sites that the Phase II survey was conducted from 2007 to 2009 after considering the results of Phase I for abandoned mines scattered all over the country. 12 study sites were classified into four types; Type I sites only have pit mouth. Type II sites have pit mouth and mine-waste field. Type III sites have pit mouth and tailing sorting field. Type IV sites have pit mouth, tailing sorting field and concentrator(s). In forest land, paddy soil and farm land of Type I, As and Cd were showed average concentration, and Cu and Pb were high on the pit mouth area in one mines where the pit mouth was developed within 500 m. In the mines of Type II, Cu and Pb were showed average concentration too, but As and Cd were slightly high in pit mouth and mine-waste field. The mines of Type III which had grinding particle process through physical separation milling or hitting showed similar tendency with Type II. However, mines of Type IV pit mouth, mine-waste field and showed various results depending on defining the contamination sources. For example, if contamination source was pit mouth, the mixed results of Type I, II, II were showed. In tailing sorting field which was regarded as the most important source and having high mobility, however, if there were no facilities or it was difficult to access directly, field sampling was missed occasionally during phase I and phase II survey. For that reason, the assessment for tailing sorting field is missed and it leads to completely different results. In the areas of Type I mines, the concentration of heavy metals exceeded precautionary standards of soil contamination or not within 1,000 meters of pit mouth. Nickel(Ni) was the largest factor of the heavy metal contamination in this type. The heavy metals except Arsenic(As) were shown high levels of concentration in Type II areas, where pit mouth and mine-waste field were operated for making powder in upriver region; therefore, to the areas in the vicinity of midstream and downstream, the high content of heavy metals were shown. The tendency of high level of heavy metals and toxic materials contained in flotation agent used during sorting process were found in soil around sorting and tailing field. In the abandoned-pit-mouth area, drygrinding area and tailing sorting field area, the content of Cupper(Cu) and Zinc(Zn) were higher than other areas. Also, the contaminated area were larger than mine reclamation area(2,000 m) and the location of tailing sorting field was one of the important factors to estimate contaminated area.

• KEPCO Journal on Electric Power and Energy
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• 제6권4호
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• pp.467-472
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• 2020

The superconducting synchronous generator is one of the breakthrough elements for direct-drive wind turbines because it is light and small. Normally the superconducting one has copper armature windings in the stator and superconducting field windings on the rotor. The high resistance of the armature can make large copper losses, comparing with the conventional generators with a gear box. One of the solutions for the large copper losses could be a fully superconducting generator. But the high magnetic fields from the superconducting field windings on the rotor also make high perpendicular magnetic fields on the superconducting tapes in the armature windings. We have proposed a fully superconducting synchronous generator with dual field windings. It could immensely decrease the circumferential component of the magnetic field from the field windings at the armature windings. In this paper, we conceptually designed 3 types of superconducting synchronous generators. The first one is the fully superconducting one with conventional structure, which has superconducting armature windings in the stator and superconducting field windings on the rotor. The second one is the one with dual superconducting field windings and superconducting armature windings between them. The last one is the same as the third one except the structure of the armature. If the concentrated armature windings are superconducting ones with cryostats, then they cannot be installed within the span of 2 poles. So, we adopted 3 phases windings within 4 poles system. It makes more AC losses but can be manufactured really.

• 직업교육연구
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• 제36권1호
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• pp.23-46
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• 2017

이 연구의 목적은 공업계열 특성화고 및 마이스터고 학생의 인성 수준을 분석하는 것이며, 이를 통해 인성교육과 추후 연구에 활용할 수 있는 기초자료를 제공하고자 한다. 이를 위한 연구 목표는 공업계열 특성화고 학생 및 마이스터고 학생의 인성 수준 및 배경 변인별 차이를 분석하는 것이다. 이 연구의 모집단은 공업계열 특성화고 및 마이스터고 전체 학생인 162,075명이며, 특성화고와 마이스터고 각각 500명, 총 1000명의 학생을 대상으로 설문 조사를 실시하였다. 조사 도구는 현주 외(2014)가 개발한 설문 도구를 본 연구 목적에 맞게 재구성하였고, 이에 요인분석과 내용타당도 검증을 실시하여 설문 도구에 대한 타당도를 확보하였다. 연구 결과는 다음과 같다. 첫째, 공업계열 특성화고 학생은 10개 덕목 모두에서 보통 이상의 인성 수준을 나타냈지만 이는 현주 외(2014)에서 제시한 고등학생 평균치에 미치지 못하는 수치였다. 둘째, 공업계열 마이스터고 학생은 10개 덕목 모두에서 보통 이상의 인성 수준을 나타냈고, 이는 현주 외(2014)에서 제시한 고등학생 평균과 비교했을 때 배려 소통, 예의, 정직 용기, 정의 영역에서 평균치 이하의 수치가 나타났다. 셋째, 공업계열 특성화고 및 마이스터고 학생은 부모의 가치관, 교사 존경 여부, 성적 스트레스, 학교 만족에 따라 인성 수준에 차이가 나타났으며, 추가적으로 마이스터고 학생은 진로계획에 따라 인성 수준에서 차이가 나타났다. 즉, 부모가 자신의 성적보다는 행복을 더 중시한다고 생각했을 때, 교사를 존경하는 학생이, 학교생활에 만족하는 학생이 더 높은 인성 수준을 보였고, 마이스터고 학생의 경우 진로를 결정하지 못한 학생에 비해 구체적인 자신의 진로를 계획하고 있는 학생이 더 높은 인성 수준을 나타냈다.

• 대한전기학회논문지
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• 제35권12호
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• pp.579-585
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• 1986

A Reversed Field Pinch(RFP) Plasma automatically forms the reversed field configuration in a stable state by the self-reversal phenomenon. But this process of formation of the reversed field configuration has a problem that instabilities occur. In order to form a RFP configuration in a stable state by removing instabilities, this experimental study attempts to restrain Toroidal magnetic fields and supplement Toroidal flux by employing high frequency rotating fields. As a result, the reversed magnetic field configuration is stably formed in a short period because high frequency rotating fields can deflect poloidal currents and produce magnetic fields in the Toroidal direction.